Light emitting diodes with n-polarity and associated methods of manufacturing

ABSTRACT

Light emitting diodes (“LEDs”) with N-polarity and associated methods of manufacturing are disclosed herein. In one embodiment, a method for forming a light emitting diode on a substrate having a substrate material includes forming a nitrogen-rich environment at least proximate a surface of the substrate without forming a nitrodizing product of the substrate material on the surface of the substrate. The method also includes forming an LED structure with a nitrogen polarity on the surface of the substrate with a nitrogen-rich environment.

TECHNICAL FIELD

The present technology is directed generally to solid state lighting(SSL) devices, such as light emitting diodes (“LEDs”), and associatedmethods of manufacturing.

BACKGROUND

Mobile phones, personal digital assistants (PDAs), digital cameras, MP3players, and other portable electronic devices utilize LEDs forbackground illumination. FIG. 1 is a cross-sectional diagram of aportion of a conventional indium-gallium nitride (“InGaN”) LED 10. Asshown in FIG. 1A, the LED 10 includes a substrate 12, an optional buffermaterial 13 (e.g., aluminum nitride), an N-type gallium nitride (“GaN”)material 14, an InGaN material 16 (and/or GaN multiple quantum wells),and a P-type GaN material 18 on top of one another in series. The LED 10also includes a first contact 20 on the P-type GaN material 18 and asecond contact 22 on the N-type GaN material 14.

The LED 10 should be configurable to emit at a wide range ofwavelengths. It is believed that the wavelength at which the LED 10emits is at least partially related to the amount of indium (In) in theInGaN material 16. For example, a larger amount of indium in the InGaNmaterial 16 has been associated with longer emission wavelengths of theLED 10.

One technique for enhancing the incorporation of indium in the InGaNmaterial 16 is to form the GaN/InGaN materials 14, 16, and 18 onnitrogen-polarity surfaces rather than on gallium-polarity surfaces vianitrodizing the substrate 12. However, one operational difficulty ofthis technique is that the nitrodizing product of the substrate 12 mayinterfere with subsequent deposition of the GaN/InGaN materials 14, 16,and 18 thereon. Thus, several improvements in forming LED structures onnitrogen-polarity surfaces of substrates may be desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a cross-sectional view of a portion of an LED in accordancewith the prior art.

FIG. 1B is a schematic perspective view of a crystal plane in aGaN/InGaN material in accordance with embodiments of the technology.

FIG. 2 is a flow diagram illustrating a method for forming an LEDstructure with N-polarity in accordance with embodiments of thetechnology.

FIG. 3A is a flow diagram illustrating a procedure for generating anitrogen-rich environment at a substrate surface in accordance withembodiments of the technology.

FIG. 3B is a schematic diagram illustrating a plasma reactor useful forperforming the procedure of FIG. 3A in accordance with embodiments ofthe technology.

FIG. 3C is a cross-sectional diagram illustrating a portion of asubstrate treated in the plasma reactor of FIG. 3B in accordance withembodiments of the technology.

FIGS. 4A-4C are cross-sectional diagrams illustrating a portion of asubstrate undergoing another procedure for generating a nitrogen-richenvironment at a substrate surface in accordance with embodiments of thetechnology.

FIG. 5 is a flow diagram illustrating a method for forming an LEDstructure with N-polarity in accordance with further embodiments of thetechnology.

DETAILED DESCRIPTION

Various embodiments of microelectronic substrates having LEDs formedthereon and associated methods of manufacturing are described below. Theterm “microelectronic substrate” is used throughout to includesubstrates upon which and/or in which microelectronic devices,micromechanical devices, data storage elements, read/write components,and other features are fabricated. The term “silicon” generally refersto a single crystalline silicon material having a face-centered diamondcubic structure with a lattice spacing of 5.430710Å. The term “silicon(1,0,0)” and the term “silicon (1,1,1)” generally refer to crystallattice orientations of (1,0,0) and (1,1,1) as defined by the Millerindex, respectively. A discussion of the Miller index can be found inthe Handbook of Semiconductor Silicon Technology by William C. O'Mara,the disclosure of which is incorporated herein in its entirety. A personskilled in the relevant art will also understand that the technology mayhave additional embodiments, and that the technology may be practicedwithout several of the details of the embodiments described below withreference to FIGS. 2A-5.

In the following discussion, an LED having GaN/InGaN materials is usedas an example of an LED in accordance with embodiments of thetechnology. Several embodiments of the LEDs may also include at leastone of gallium arsenide (GaAs), aluminum gallium arsenide (AlGaAs),gallium arsenide phosphide (GaAsP), aluminum gallium indium phosphide(AlGaInP), gallium(III) phosphide (GaP), zinc selenide (ZnSe), boronnitride (BN), aluminum nitride (AlN), aluminum gallium nitride (AlGaN),aluminum gallium indium nitride (AlGaInN), and/or other suitablesemiconductor materials. The foregoing semiconductor materials may havegenerally similar or different crystal structures than GaN/InGaNmaterials. However, the following definition of Ga-polarity andN-polarity may still apply.

FIG. 1B is a schematic perspective view of a crystal plane in aGaN/InGaN material in accordance with embodiments of the technology. Asshown in FIG. 1B, the GaN/InGaN material has a wurtzite crystalstructure with various lattice planes or facets as represented bycorresponding Miller indices. One such lattice plane, the c-plane, isillustrated in FIG. 1B. As used hereinafter, the term “Ga-polarity”generally refers to a lattice structure extending along a directiongenerally perpendicular to the c-plane and with a Miller index of[0001]. The term “N-polarity” generally refers to a lattice structureextending along the opposite direction with a Miller index of [000 1].

FIG. 2 is a flow diagram illustrating a method 200 of forming an LEDstructure with N-polarity in accordance with embodiments of thetechnology. As shown in FIG. 2, an initial stage of the method (block202) includes generating a nitrogen-rich environment at least proximatea surface of a substrate without forming a nitride material on thesurface of the substrate. In the following description, the substrateincludes a silicon wafer with a (1,1,1) crystal lattice orientation forillustration purposes. In other embodiments, the substrate can alsoinclude a silicon wafer with a (1,0,0) crystal lattice orientation. Infurther embodiments, the substrate can include a silicon wafer withother crystal lattice orientations, or it can include silicon carbide(SiC), sapphire (Al₂O₃), and/or other suitable substrate materials.

One feature of the generated nitrogen-rich environment at the surface ofthe substrate is that the nitrogen (N) atoms may be loosely adsorbed on,diffused into, and/or otherwise attached to the surface of the siliconwafer without forming covalent bonds, ionic bonds, and/or having otherstrong interactions with the silicon material. As used hereinafter, thephrase “strong interaction” generally refers to a molecular interactionwith an interaction energy of more than about 50 kcal/mol.

Instead, in certain embodiments, the nitrogen atoms may be adsorbed ontothe surface of the silicon wafer via Van der Waals forces, hydrogenbonds, and/or other weak interactions. As used hereinafter, the phrase“weak interaction” generally refers to a molecular interaction with aninteraction energy of less than about 10.0 kcal/mol. For example, thenitrogen atoms may be attached to the surface of the silicon wafer viaVan der Waals forces or hydrogen bonds with an interaction energy ofabout 10.0 kcal/mol, 5 kcal/mol, 1 kcal/mol, and/or with other suitablevalues of interaction energy. In another embodiment, the nitrogen atomsmay be defused into the silicon wafer. The diffused nitrogen atoms maybe contained or trapped in the lattice structure of the silicon waferwithout forming silicon nitride (SiN) crystal structures. In furtherembodiments, the nitrogen atoms may be otherwise loosely attached to thesubstrate via other suitable mechanisms.

In certain embodiments, generating the nitrogen-rich environment caninclude applying nitrogen plasma from which a plurality of nitrogenatoms attach to the surface of the silicon wafer, and controlling theparameters of the nitrogen plasma to avoid forming silicon nitride (SiN)and/or other nitrodizing products on the surface of the silicon wafer.Several embodiments utilizing the application of nitrogen plasma aredescribed in more detail below with reference to FIGS. 3A-3C.

In other embodiments, generating the nitrogen-rich environment caninclude depositing silicon nitride (SiN) and/or other nitrodizingproducts on the surface of the silicon wafer, diffusing at least some ofthe nitrogen atoms from the silicon nitride (SiN) into the siliconwafer, and subsequently removing the deposited silicon nitride (SiN)from the surface of the silicon wafer before forming LED structuresthereon. Several embodiments utilizing the diffusion of nitrogen atomsinto the silicon wafer are described in more detail below with referenceto FIGS. 4A-4D. In further embodiments, generating the nitrogen-richenvironment can include contacting the surface of the silicon wafer withother suitable nitrogen-containing compositions.

After the nitrogen-rich environment is generated, the method can theninclude several stages of forming an LED structure on the surface of thesilicon wafer. For example, another stage of the method (block 204) caninclude depositing a first semiconductor material on the silicon waferthat has the nitrogen-rich environment at least proximate the surface ofthe silicon wafer. In one embodiment, depositing the first semiconductormaterial includes growing an epitaxial N-type GaN material on thesurface of a silicon wafer. In other embodiments, depositing the firstsemiconductor material may include growing a P-type GaN material and/orother suitable cladding materials on the surface of the silicon wafer.

A further stage of the method (block 206) can include forming an activeregion of the LED on the first semiconductor material. In oneembodiment, forming the active region includes growing an epitaxialInGaN material and/or forming GaN multiple quantum wells on the N-typeGaN material grown on the surface of the substrate. In otherembodiments, forming the active region can include growing other typesof suitable semiconductor material on the first semiconductor material.

Yet another stage of the method (block 208) can include forming a secondsemiconductor material on the active region. In one embodiment,depositing the second semiconductor material includes growing anepitaxial P-type GaN material on the active region of the LED. In otherembodiments, depositing the second semiconductor material may alsoinclude growing an N-type GaN material and/or other suitable claddingmaterials. Techniques for growing the first semiconductor material, theactive region, and the second semiconductor material can includemetal-organic chemical vapor deposition (“MOCVD”), molecular beamepitaxy (“MBE”), liquid phase epitaxy (“LPE”), hydride vapor phaseepitaxy (“HVPE”), and/or other suitable techniques.

It is believed that the nitrogen-rich environment at the surface of thesilicon wafer can at least facilitate the growth of GaN/InGaN materialswith N-polarity instead of the Ga-polarity for the LED structure.Without being bound by theory, it is believed that the nitrogen atoms atleast proximate the surface of the silicon wafer can influence and/ordetermine the polarity of an electrical and/or electromagnetic field atthe surface of the silicon wafer. As a result, gallium (Ga) and/orindium (In) atoms would preferentially form GaN and/or InGaN latticestructures with the N-polarity instead of the Ga-polarity.

It is also believed that the formed LED structure can have improvedlattice quality over prior art LED structures because no silicon nitride(SiN) is formed on the surface of the silicon wafer. Without being boundby theory, it is believed that if silicon nitride (SiN) is formed on thesurface of the silicon wafer, precursors for forming the GaN and/orInGaN materials (e.g., trimethylgallium, triethylgallium,trimethylindium, triethylindium, di-isopropylmethylindium,ethyldimethylindium, etc.) may not adequately wet the surface of thesilicon wafer. As a result, it may be difficult for the GaN/InGaNprecursors to nucleate on the surface of the silicon wafer. The formedLED structure thus would have high dislocation rates, rough surfaces,and/or other poor lattice qualities. Accordingly, by not forming siliconnitride (SiN) on the surface of the silicon wafer, the GaN/InGaNprecursors may readily nucleate on the surface of the silicon wafer toyield improved lattice qualities for the formed LED structure.

Even though the method 200 is described above as forming the LEDstructure directly on the surface of the silicon wafer, in certainembodiments the method 200 can also include optionally depositing abuffer material onto the surface of the silicon wafer before forming theLED structure. In one embodiment, the buffer material can includealuminum nitride (AlN) formed by contacting the surface of the siliconwafer with a gas containing trimethylaluminum (TMAl), ammonia (NH₄OH),and/or other suitable compositions. In other embodiments, the buffermaterial can also include zinc oxide (ZnO₂) and/or other suitable buffermaterials formed on the surface of the silicon wafer via MOCVD, MBE,and/or other suitable techniques.

FIG. 3A is a flow diagram illustrating a procedure 300 for generating anitrogen-rich environment at least proximate a surface of a siliconwafer in accordance with embodiments of the technology. As shown in FIG.3A, the procedure 300 can include an initial stage (block 302) ofplacing a silicon wafer in a plasma reactor and/or other suitable typesof reactors. One example of a plasma reactor is discussed below in moredetail with reference to FIG. 3B.

Another stage of the procedure 300 (block 304) includes generatingnitrogen plasma in the plasma chamber. In one embodiment, generatingnitrogen plasma includes injecting a gas containing nitrogen into theplasma chamber, and applying energy to the injected gas to generate thenitrogen plasma in the plasma chamber. Techniques for applying energyinclude electrostatic biasing, radio frequency (“RF”) radiating, and/orother suitable techniques. In another embodiment, the nitrogen plasmamay be generated by a remote plasma source and may be directed to theplasma chamber with a plasma guide. In further embodiments, the nitrogenplasma may be generated via other suitable techniques.

A subsequent stage of the procedure 300 (block 306) includes applyingthe generated plasma to the surface of the silicon wafer. While applyingthe nitrogen plasma to the surface of the silicon wafer, another stageof the procedure 300 (block 308) includes adjusting at least oneparameter of generating and/or applying the nitrogen plasma such thatthe generated nitrogen plasma does not cause silicon nitride (SiN) to beformed on the surface of the silicon wafer.

In one embodiment, a plasma sensor can continuously measure at least oneplasma parameter (e.g., a plasma charge density and/or a plasmatemperature) of the generated plasma. A computer-based controller maythen use the monitored plasma parameter as a process variable in afeedback-control loop for achieving a desired setpoint of plasma energy.The setpoint of the plasma energy may be empirically and/ortheoretically determined such that the nitrogen plasma does not havesufficient energy to cause formation of silicon nitride (SiN) on thesurface of the silicon wafer. Control variables for the feedback-controlloop may include electrical biasing voltage, RF intensity, thermal inputto the plasma chamber and/or the silicon wafer, and/or other suitableoperating conditions. In other embodiments, other suitable techniquesand/or operating parameters of the generated plasma may be used.

FIG. 3B is a schematic diagram illustrating a plasma reactor 310 usefulfor performing the procedure 300 of FIG. 3A in accordance withembodiments of the technology. As shown in FIG. 3B, the plasma reactor310 includes a chamber 311, a support 312 inside the chamber 311, and apower source 314 electrically coupled to the support 312. The chamber311 includes a vessel 316 coupled to an electrically grounded lid 318 toform a sealed environment inside the chamber 311. The chamber 311 alsoincludes a gas inlet 320 proximate to an upper portion of the vessel 316and a gas outlet 322 proximate to a bottom portion of the vessel 316.The plasma reactor 310 can also include a vacuum pump (not shown)coupled to the gas outlet 322 for evacuating gases from the chamber 311.

In operation, a gas containing nitrogen enters the chamber 311 via thegas inlet 320. The power source 314 creates a bias voltage between thesupport 312 and the lid 318 to establish and/or to maintain plasma 324between the lid 318 and a silicon wafer 328 held on the support 312. Theplasma 324 can then form a nitrogen-rich environment proximate to asurface of the silicon wafer 328 without forming silicon nitride (SiN),as discussed in more detail below with reference to FIG. 3C.

FIG. 3C is a cross-sectional diagram illustrating a portion of thesilicon wafer 328 processed in the plasma reactor 310 of FIG. 3B inaccordance with embodiments of the technology. As shown in FIG. 3C, thesilicon wafer 328 includes a plurality of silicon atoms 330 proximate toa surface 329 of the silicon wafer 328. Though not illustrated, thesurface 329 may be oxygen terminated, hydroxyl terminated, and/or havingother suitable termination groups.

A plurality of nitrogen atoms 332 can be adsorbed and/or otherwiseattached to the surface 329 of the silicon wafer 328 via weakinteractions. For example, the nitrogen atoms 332 may be attached to thesurface 329 of the silicon wafer via Van der Waals forces or hydrogenbonds. Unlike prior art techniques, the nitrogen atoms 332 are notattached to the surface 329 of the silicon wafer 328 via covalent bonds,ionic bonds, and/or other strong interactions. As a result, the nitrogenatoms 332 do not form silicon nitride (SiN) on the surface 329 of thesilicon wafer 328.

FIGS. 4A-4C are cross-sectional diagrams illustrating a portion of asubstrate 402 undergoing a procedure 400 for generating a nitrogen-richenvironment at least proximate a surface 404 in accordance withembodiments of the technology. As shown in FIG. 4A, an initial stage ofthe procedure 400 can include depositing a nitride material 406 on thesurface 404 of the substrate 402. The nitride material 406 can includesilicon nitride (SiN), aluminum nitride (AlN), and/or other suitablenitride materials with a thickness T. Techniques for depositing thenitride material 406 can include chemical vapor deposition (CVD), atomiclayer deposition (ALD), MOCVD, MBE, and/or other suitable techniques. Inone embodiment, the nitride material 406 may be generally amorphous. Inother embodiments, the nitride material 406 may be partiallycrystalline.

A subsequent stage of the procedure 400 can include causing at leastsome of the nitrogen from the nitride material 406 to migrate toward thesurface 404 of the substrate 402. In one embodiment, heat (asrepresented by the arrows 408) may be applied to facilitate themigration of nitrogen atoms. In other embodiments, electromagneticradiation and/or other suitable techniques may be used to facilitate themigration of nitrogen atoms.

As shown in FIG. 4B, the migrated nitrogen atoms can form anitrogen-rich layer 410 proximate to the surface 404 of the substrate402. At least one operating parameter (e.g., an amount of heat, aradiation intensity, a duration of radiation and/or heat, etc.) may beadjusted so that the migrated nitrogen atoms do not form a nitrodizedproduct with the substrate material. Instead, the migrated nitrogenatoms may be contained or trapped in the lattice structure of thesubstrate 402.

Another stage of the procedure 400 can include removing the nitridematerial 406 from the surface 404 of the substrate 402 prior toformation of LED structures on the surface 404 of the substrate 402. Inone embodiment, removing the nitride material 406 can include wetetching the nitride material 406 and selecting at least one of anetching time, etching temperature, and etchant composition based on thethickness T of the nitride material 406. In other embodiments, removingthe nitride material 406 can include laser ablation, dry etching, and/orusing other suitable techniques. The procedure 400 can then includeforming an LED structure on the substrate 402 with the nitrogen-richlayer 410 as discussed with reference to FIGS. 2.

FIG. 5 is a flow diagram illustrating a method 500 for forming an LEDstructure with N-polarity in accordance with further embodiments of thetechnology. As shown in FIG. 5, an initial stage of the method 500(block 502) can include forming an N-polarity GaN material on asubstrate. The substrate can include silicon (Si), silicon carbide(SiC), sapphire (Al₂O₃), and/or other suitable substrate materials.

In one embodiment, forming an N-polarity GaN material can includedepositing GaN with heavy magnesium (Mg) doping onto the substrate viaMOCVD, MEB, LPE, HVPE, and/or other suitable types of depositiontechniques. Without being bound by theory, it is believed that when themagnesium doping concentration is above a threshold (e.g., about1×E²⁰/cm⁻³), the GaN formed on the substrate is substantiallyN-polarity. Thus, forming an N-polarity GaN material can also includeadjusting at least one of the magnesium doping concentration, dopingcondition, and/or other suitable operation parameters to achieve adesired N-polarity lattice structure in the GaN material. In otherembodiments, forming an N-polarity GaN material can also includedepositing GaN with other types of suitable dopants. The method 500 canthen include depositing a first LED semiconductor material, forming anactive region of the LED, and depositing a second LED semiconductormaterial, as discussed in more detail above with reference to FIG. 2.

From the foregoing, it will be appreciated that specific embodiments ofthe technology have been described herein for purposes of illustration,but that various modifications may be made without deviating from thedisclosure. For example, several embodiments of the procedure 300 mayinclude forming at least some nitride material on the surface of thesilicon wafer and subsequently removing the nitride material beforeforming the LED structure. In other examples, several embodiments of theprocedures 300 and 400 may be performed in MOCVD, MEB, LPE, HVPE, and/orother suitable types of deposition systems. Many of the elements of oneembodiment may be combined with other embodiments in addition to or inlieu of the elements of the other embodiments. For example, severalembodiments of the procedure 300 may also include causing some of thenitrogen atoms to migrate toward the surface of the silicon wafer beforeremoving the nitride material, as discussed with reference to FIGS.4A-4C. Accordingly, the disclosure is not limited except as by theappended claims.

1. A method for forming a light emitting diode (LED), comprising:exposing a surface of a substrate to a nitrogen-containing composition,the substrate having a substrate material; generating a nitrogen-richenvironment at least proximate the surface of the substrate with thenitrogen-containing composition; adjusting at least one operatingparameter of exposing the surface of the substrate to thenitrogen-containing composition such that the nitrogen-containingcomposition does not react with the substrate material to form anitrodizing product; and forming an LED structure on the surface of thesubstrate with the nitrogen-rich environment, the LED structure having anitrogen polarity.
 2. The method of claim 1 wherein: the substrateincludes a silicon wafer; the substrate material includes silicon (Si);exposing the surface of the substrate includes: generating a nitrogenplasma; directing the nitrogen plasma toward the surface of the siliconwafer; generating the nitrogen-rich environment includes adsorbingnitrogen atoms from the nitrogen plasma onto the surface of the siliconwafer via Van der Waals forces; adjusting the at least one operatingparameter includes adjusting at least one of a plasma charge density anda plasma temperature such that the nitrogen plasma does not react withsilicon at the surface of the silicon wafer to form silicon nitride(SiN); and forming the LED structure includes sequentially depositingN-type gallium nitride (GaN), indium-gallium nitride (InGaN), and P-typeGaN materials on the surface of the silicon wafer.
 3. The method ofclaim 1 wherein: the substrate includes a silicon wafer; the substratematerial includes silicon (Si); exposing the surface of the substrateincludes depositing silicon nitride (SiN) on the surface of the siliconwafer, the deposited silicon nitride containing a plurality of nitrogen(N) atoms; generating the nitrogen-rich environment includes causing atleast some of the nitrogen (N) atoms to migrate into the surface of thesilicon wafer via heating and/or radiation; and adjusting the at leastone operating parameter includes adjusting at least one of an amount ofheat, a radiation intensity, a duration of radiation and/or heat suchthat the migrated nitrogen (N) atoms do not react with silicon at thesurface of the silicon wafer to form silicon nitride (SiN); and themethod further includes removing the deposited silicon nitride (SiN)from the surface of the silicon wafer; and forming the LED structureincludes sequentially depositing N-type GaN, InGaN, and P-type GaNmaterials on the surface of the silicon wafer after the silicon nitride(SiN) is removed from the surface of the silicon wafer.
 4. The method ofclaim 1 wherein: the substrate includes a silicon wafer; the substratematerial includes silicon (Si); and adjusting the at least one operatingparameter includes adjusting at least one operating parameter such thatthe nitrogen-containing composition does not react with silicon at thesurface of the silicon wafer to form silicon nitride (SiN).
 5. Themethod of claim 1 wherein: the substrate includes a silicon wafer; thesubstrate material includes silicon (Si); and generating thenitrogen-rich environment includes adsorbing a plurality of nitrogen (N)atoms onto the surface of the silicon wafer without forming siliconnitride (SiN) on the surface of the silicon wafer.
 6. The method ofclaim 1 wherein: the substrate includes a silicon wafer; the substratematerial includes silicon (Si); exposing the surface of the substrateincludes: generating a nitrogen plasma; and directing the nitrogenplasma toward the surface of the silicon wafer; and generating thenitrogen-rich environment includes adsorbing a plurality of nitrogen (N)atoms from the nitrogen plasma onto the surface of the silicon waferwithout forming silicon nitride (SiN) on the surface of the siliconwafer.
 7. The method of claim 1 wherein: the substrate includes asilicon wafer; the substrate material includes silicon (Si); exposingthe surface of the substrate includes: generating a nitrogen plasma; anddirecting the nitrogen plasma toward the surface of the silicon wafer;generating the nitrogen-rich environment includes adsorbing a pluralityof nitrogen (N) atoms from the nitrogen plasma onto the surface of thesilicon wafer; and adjusting the at least one operating parameterincludes adjusting at least one of a plasma charge density and a plasmatemperature of the nitrogen plasma such that the nitrogen plasma doesnot react with silicon at the surface of the silicon wafer to formsilicon nitride (SiN).
 8. The method of claim 1 wherein: the substrateincludes a silicon wafer having a lattice structure; the substratematerial includes silicon (Si); exposing the surface of the substrateincludes depositing silicon nitride (SiN) on the surface of the siliconwafer, the deposited silicon nitride containing a plurality of nitrogen(N) atoms; generating the nitrogen-rich environment includes causing atleast some of the nitrogen (N) atoms to migrate into the surface of thesilicon wafer, the migrated nitrogen (N) atoms being trapped in thelattice structure of the silicon wafer without forming a silicon nitride(SiN) crystal structure with the silicon (Si) in the silicon wafer. 9.The method of claim 1 wherein: the substrate includes a silicon wafer;the substrate material includes silicon (Si); exposing the surface ofthe substrate includes depositing silicon nitride (SiN) on the surfaceof the silicon wafer, the deposited silicon nitride containing aplurality of nitrogen (N) atoms; and generating the nitrogen-richenvironment includes causing at least some of the nitrogen (N) atoms tomigrate into the surface of the silicon wafer; and the method furtherincludes removing the deposited silicon nitride (SiN) from the surfaceof the silicon wafer before forming the LED structure.
 10. The method ofclaim 1 wherein: the substrate includes a silicon wafer having a latticestructure; the substrate material includes silicon (Si); exposing thesurface of the substrate includes depositing silicon nitride (SiN) onthe surface of the silicon wafer, the deposited silicon nitridecontaining a plurality of nitrogen (N) atoms; and generating thenitrogen-rich environment includes causing at least some of the nitrogen(N) atoms to migrate into the surface of the silicon wafer, the migratednitrogen (N) atoms being trapped in the lattice structure of the siliconwafer without forming a silicon nitride (SiN) crystal structure with thesilicon (Si) in the silicon wafer; and the method further includesremoving the deposited silicon nitride (SiN) from the surface of thesilicon wafer before forming the LED structure.
 11. A method for formingan LED, comprising: exposing a surface of a substrate to anitrogen-containing composition, the substrate having a substratematerial; increasing a nitrogen (N) concentration in the substratematerial at least proximate the surface of the substrate with thenitrogen-containing composition without forming a nitrodizing product ofthe substrate material; and forming an LED structure on the surface ofthe substrate with a nitrogen-rich environment, the LED structure havinga nitrogen polarity.
 12. The method of claim 11 wherein: the substrateincludes a silicon wafer; the substrate material includes silicon (Si);and increasing the nitrogen (N) concentration includes adsorbing aplurality of nitrogen (N) atoms onto the surface of the silicon waferwithout forming silicon nitride (SiN) on the surface of the siliconwafer.
 13. The method of claim 11 wherein: the substrate includes asilicon wafer; the substrate material includes silicon (Si); andincreasing the nitrogen (N) concentration includes: contacting thesurface of the silicon wafer with a nitrogen plasma; and adsorbing aplurality of nitrogen (N) atoms from the nitrogen plasma onto thesurface of the silicon wafer without forming silicon nitride (SiN) onthe surface of the silicon wafer.
 14. The method of claim 11 wherein:the substrate includes a silicon wafer; the substrate material includessilicon (Si); and increasing the nitrogen (N) concentration includes:applying a nitrogen plasma to the surface of the silicon wafer;adsorbing a plurality of nitrogen (N) atoms from the nitrogen plasmaonto the surface of the silicon wafer; and controlling the energy of theapplied nitrogen plasma such that the nitrogen plasma does not reactwith silicon (Si) in the silicon wafer to form silicon nitride (SiN) onthe surface of the silicon wafer.
 15. The method of claim 11 wherein:the substrate includes a silicon wafer; the substrate material includessilicon (Si); and increasing the nitrogen (N) concentration includes:applying a nitrogen plasma to the surface of the silicon wafer;adsorbing a plurality of nitrogen (N) atoms from the nitrogen plasmaonto the surface of the silicon wafer; and controlling the energy of theapplied nitrogen plasma such that the adsorbed nitrogen atoms areadsorbed on the surface of the silicon wafer via a molecular interactionhaving an interaction energy less than about 10 kcal/mol.
 16. The methodof claim 11 wherein: the substrate includes a silicon wafer; thesubstrate material includes silicon (Si); and increasing the nitrogen(N) concentration includes: applying a nitrogen plasma to the surface ofthe silicon wafer; attaching a plurality of nitrogen (N) atoms from thenitrogen plasma onto the surface of the silicon wafer; and controllingthe energy of the applied nitrogen plasma such that the nitrogen atomsare attached on the surface of the silicon wafer not via a molecularinteraction having an interaction energy greater than about 50 kcal/mol.17. The method of claim 11 wherein: the substrate includes a siliconwafer; the substrate material includes silicon (Si); and increasing thenitrogen (N) concentration includes migrating a plurality of nitrogen(N) atoms into the surface of the silicon wafer without forming siliconnitride (SiN) on the surface of the silicon wafer.
 18. The method ofclaim 11 wherein: the substrate includes a silicon wafer; the substratematerial includes silicon (Si); the method further includes depositingsilicon nitride (SiN) onto the surface of the silicon wafer; andincreasing the nitrogen (N) concentration includes migrating a pluralityof nitrogen (N) atoms from the deposited silicon nitride (SiN) into thesurface of the silicon wafer without forming silicon nitride (SiN) onthe surface of the silicon wafer.
 19. The method of claim 11 wherein:the substrate includes a silicon wafer; and the substrate materialincludes silicon (Si); the method further includes depositing siliconnitride (SiN) onto the surface of the silicon wafer; and increasing thenitrogen (N) concentration includes migrating a plurality of nitrogen(N) atoms from the deposited silicon nitride (SiN) into the surface ofthe silicon wafer without forming silicon nitride (SiN) on the surfaceof the silicon wafer; and the method further includes removing thedeposited silicon nitride (SiN) from the surface of the silicon waferbefore forming the LED structure.
 20. A method for forming an LED on asubstrate having a substrate material, comprising: forming anitrogen-rich environment at least proximate a surface of the substratewithout forming a nitrodizing product with the substrate material on thesurface of the substrate; and forming an LED structure with a nitrogenpolarity on the surface of the substrate with the nitrogen-richenvironment.
 21. The method of claim 20 wherein forming thenitrogen-rich environment includes adsorbing a plurality of nitrogen (N)atoms onto the surface of the substrate without nitrodizing thesubstrate material on the surface of the substrate.
 22. The method ofclaim 20 wherein forming the nitrogen-rich environment includesadsorbing nitrogen atoms on the surface of the silicon wafer via amolecular interaction having an interaction energy less than about 10kcal/mol.
 23. The method of claim 20 wherein forming the nitrogen-richenvironment includes adsorbing nitrogen atoms on the surface of thesilicon wafer without forming ionic or covalent bonds with the substratematerial.
 24. The method of claim 20 wherein forming the nitrogen-richenvironment includes causing nitrogen atoms to migrate into the surfaceof the silicon wafer without forming ionic or covalent bonds with thesubstrate material.
 25. A light emitting diode, comprising: a substratehaving a substrate material; a first semiconductor material directly ona surface of the substrate; an active region on the first semiconductormaterial, the active region having a nitrogen-polarity crystalstructure; a second semiconductor material on the active region; andwherein the light emitting diode does not include a nitrodizing productof the substrate material at an interface between the surface of thesubstrate and the first semiconductor material.
 26. The light emittingdiode of claim 25 wherein: the substrate includes a silicon wafer havinga lattice structure; the substrate material includes silicon (Si); thefirst semiconductor material includes an N-type gallium nitride (GaN)material; the active region includes an indium gallium nitride (InGaN)material; the second semiconductor material includes a P-type GaNmaterial; and the silicon wafer includes a nitrogen-rich environment atleast proximate the surface of the silicon wafer, the nitrogen-richenvironment having a plurality of nitrogen (N) atoms trapped in thelattice structure of the silicon wafer without forming a silicon nitride(SiN) crystal structure with the silicon (Si) in the silicon wafer. 27.The light emitting diode of claim 25 wherein: the substrate includes asilicon wafer; the substrate material includes silicon (Si); the firstsemiconductor material includes an N-type gallium nitride (GaN)material; the active region includes an indium gallium nitride (InGaN)material; the second semiconductor material includes a P-type GaNmaterial; and the light emitting diode does not include crystallinesilicon nitride (SiN) at the interface between the surface of thesilicon wafer and the N-type GaN material.
 28. The light emitting diodeof claim 25 wherein: the substrate includes a silicon wafer; thesubstrate material includes silicon (Si); and the light emitting diodedoes not include crystalline silicon nitride (SiN) at the interfacebetween the surface of the silicon wafer and the first semiconductormaterial.
 29. A method for forming a light emitting diode (LED),comprising: forming a gallium nitride (GaN) material on a substrate witha dopant; adjusting a concentration of the dopant such that the formedGaN material has substantially nitrogen polarity; and forming an LEDstructure on the formed GaN material with the nitrogen polarity, the LEDstructure also having a nitrogen polarity.
 30. The method of claim 29wherein: forming a GaN material includes depositing the GaN materialwith a magnesium dopant, the magnesium dopant having a concentration ofat least about 1×E²⁰/cm⁻³ in the GaN material; and adjusting aconcentration of the dopant includes adjusting a concentration of themagnesium dopant such that the formed GaN material has substantiallynitrogen polarity.